Devices for capturing and storing bodily fluid intravaginally are commercially available and known in the literature. Intravaginal tampons are the most common example of such devices. Commercially available tampons are generally compressed cylindrical masses of absorbent fibers that may be over-wrapped with an absorbent or nonabsorbent cover layer.
The tampon is inserted into the human vagina and retained there for a time for the purpose of capturing and storing intravaginal bodily fluids, most commonly menstrual fluid. As intravaginal bodily fluid contacts the tampon, it should be absorbed and retained by the absorbent material of the tampon. After a time, the tampon and its retained fluid is removed and disposed, and if necessary, another tampon is inserted.
A drawback often encountered with commercially available tampons is the tendency toward premature failure, which may be defined as bodily fluid leakage from the vagina while the tampon is in place, and before the tampon is completely saturated with the bodily fluid. The patent art typically describes a problem believed to occur that an unexpanded, compressed tampon is unable to immediately absorb fluid. Therefore, it presumes that premature leakage may occur when bodily fluid contacts a portion of the compressed tampon, and the fluid is not readily absorbed. The bodily fluid may bypass the tampon.
To overcome this problem of premature leakage, extra elements have been incorporated into a basic tampon to try to direct and control the flow of fluid toward the absorbent core.
For example, U.S. Pat. No. 4,212,301 (Johnson) discloses a unitary constructed digital tampon having a lower portion compressed preferably in the radial direction to form a rigid, rod-like element, which provides a central rigidified elongated core and an upper portion left substantially uncompressed. After insertion, the uncompressed portion may be manipulated to contact the vaginal wall to provide an immediate seal against side leakage. The uncompressed portion allows for high absorbent capacity immediately upon insertion. While this tampon may allow for a certain amount of protection from bypass leakage, the uncompressed portion may become saturated before the compressed portion has a chance to expand and become absorbent.
U.S. Pat. No. 6,358,235 (Osborn et al.) discloses a “hollow” bag-like tampon that may have an interior projection made from highly compressed absorbent material. The interior projection is preferably attached to the inside surface of the head of the tampon. The hollow tampon portion may include at least one pleat in the absorbent outer surface and is soft and conformable. The tampon is not pre-compressed to the point where the fibers temporarily “set” and re-expand upon the absorption of fluid. The absorbent portions of the tampon can saturate locally, which leads to bypass leakage.
U.S. Pat. No. 6,177,608 (Weinstrauch) discloses a tampon having nonwoven barrier strips which are outwardly spreadable from the tampon surface to reliably close the free spaces believed to exist within a vaginal cavity. The nonwoven barrier strips extend about the tampon in a circumferential direction at the surface or in a helical configuration about the tampon and purportedly conduct menstrual fluid toward the tampon surface. The nonwoven barrier strips are attached to the cover by means of gluing, heat sealing, needle punching, embossing or the like and form pleats. The nonwoven barrier strips are attached to the tampon blank and the blank is embossed, forming grooves extending in a longitudinal direction. While this tampon purports to direct fluid to the core, it attempts to achieve this by forming pockets of absorbent nonwoven fabric. In order to function, it appears that these pockets would have to be opened during use to allow fluid to enter. However, based upon current understandings of vaginal pressures, it is not understood how the described structure could form such an opened volume.
U.S. Pat. No. 6,206,867 (Osborn) suggests that a desirable tampon has at least a portion of which is dry expanding to cover a significant portion of the vaginal interior immediately upon deployment. To address this desire, it discloses a tampon having a compressed central absorbent core having at least one flexible panel attached along a portion of the side surface of the core. The flexible panel appears to provide the “dry-expanding” function, and it extends outwardly from the core away from the point of attachment. The flexible panel contacts the inner surfaces of the vagina when the tampon is in place and purportedly directs fluid toward the absorbent core. The flexible panel is typically attached to the pledget prior to compression of the pledget to form the absorbent core and remains in an uncompressed state.
U.S. Pat. No. 5,817,077 (Foley et al.) discloses a method of preserving natural moisture of vaginal epithelial tissue while a using a tampon where the tampon has an initial capillary suction pressure at the outer surface of less than about 40 mm Hg. This allows the tampon to absorb vaginal secretions without substantially drying the vaginal epithelial tissue. The multiple cover layers can be used to increase the thickness of the cover material. While this represents a significant advancement in the art, this invention does not address by-pass leakage.
Additionally, U.S. Pat. No. 5,545,155 (Hseih et al.) discloses an external absorbent article that has a set of plates separated by spacer elements. The plates may be treated to affect wettability so that fluid will flow easily across the surface. Extending through the upper plate is a plurality of openings, which allow fluid to flow with little restriction into the space between the upper and lower plates. When the fluid flows downward in the z-direction from the upper plate to the lower plate, it will then flow laterally in the x- and y-directions. Therefore, this external absorbent article can contain fluid gushes, but it does not appear to address the problems relating in particular to intravaginal devices, such as a tampon.
While the prior art is replete with examples of sanitary protection articles that capture bodily fluids both externally and intravaginally, these examples do not overcome the problem of premature failure often identified as by-pass leakage that commonly occurs while using internal sanitary protection devices. Many solutions to this problem have involved increasing the rate of expansion of a highly compressed absorbent article.
Surprisingly, we have found a novel way to address the problem of premature failure. This invention is not dependent on the expansion of the compressed absorbent but rather directing the fluid by the use of inter-plate capillary action. In our invention, we minimize local saturation of the fluid storage element. Our invention also is effective for handling highly viscous menstrual fluid.